The long-range purpose of the project is to study the biochemistry, morphology, pharmacology and physiology of synaptic transmission and neuronal connections of nerve cells in mammalian cochlear nucleus. The interest is now focused on: 1) the development of a system of computer programs for storing and displaying information on the localization, synaptic connections and activity of cells in the cochlear nucleus and for controlling experiments and processing cells in the cochlear nucleus and for controlling experiments and processing results; 2) the levels of choline acetyltransferase (ChAc), glutamate decarboxylase (GAD) and tyrosine hydroxylase (TH) in the auditory nerve and the cochlear nucleus of the normal guinea pig; 3) the levels of ChAc, GAD, TH and of putative transmitter substances (amino acids and peptides) in the guinea pig cochlear nucleus after surgical destruction of the cochlea; 4) the levels of ChAc and of GAD in the normally developing cochlear nucleus and in the cochlear nucleus of a genetically deaf mutant (the waltzing guinea pig); 5) the levels of ChAc and of GAD in anatomically defined subgroups of the guinea pig cochlear nucleus. New findings indicate that it is unlikely that acetylcholine, GABA or a catecholamine is a major transmitter between the auditory nerve and the cochlear nucleus.